The invention herein described relates generally to synergistic systems and methods for preventing and/or reducing the occurrence of corrosion (including tarnishing) in a variety of articles including, but not limited to, metals, non-metals, paper articles, precious stones and semi-precious stones. More specifically, the invention herein relates to synergistic combinations of (1) a gas impermeable enclosure for holding one or more articles to be protected formed from at least one shell, where the at least one shell is adapted to maintain an internal pressure greater than an external pressure outside of the enclosure; and (2) at least one corrosion preventing device located within the gas impermeable enclosure, where the at least one corrosion preventing device is a desiccant, a corrosion inhibitor, an inert gas, and/or a combination thereof. The present invention also relates to methods which utilize synergistic systems to prevent the corrosion of a desired article.
In commerce and industry today, the useful life of corrodible items may be extended and/or preserved by providing corrosion inhibitors which protect the corrodible item from the adverse effects of its ambient environment. Among the common indications of corrosion manifested in useful metallic articles are oxidation, pitting, tarnishing, mottling, or discoloration of the surfaces of these items. These manifestations occur in metallic articles, particularly when exposed to oxygen, in either gaseous or liquid phase. Additionally, sulfides and/or chlorides (or chlorine) may cause corrosion or tarnishing problems as well. Inasmuch as both oxygen and water, including water vapor, occur normally and are available in nature, it is normally necessary to take precautions against corrosion when packaging metallic items for shipment or storage, or when subjecting such items to normal use. Metals which are frequently found to be susceptible to corrosion under normal atmospheric and ambient conditions include, but are not limited to, iron, copper, brass, aluminum, silver, and alloys of these metals.
Additionally, suitable protection may also be needed for valuable non-metal items such as precious and/or semi-precious stones and the like.
In view of the widespread need for protecting various articles from corrosion, be the articles metallic or otherwise, a variety of systems have been utilized. Such anti-corrosion systems often employ one or more of the following as components or sub components thereof: (1) a desiccant; (2) a volatile corrosion inhibitor (VCI) or a volatile corrosion inhibiting film; and/or (3) an inert atmosphere.
One such known anti-corrosion system 100 is illustrated in FIG. 1, and comprises an enclosure 104 in which an article 102 is placed in order to protect the article 102 from corrosive elements 106. The enclosure 104 can be any one of a variety of enclosures including a polymer or plastic enclosure, a paper enclosure, a metal enclosure or a metal-coated polymer enclosure. In some cases the enclosure itself can contain a volatile corrosion inhibitor and/or a desiccant. The enclosure 104 is hermetically sealed using any suitable means (e.g., heat sealing, an adhesive seal, a mechanical sealing means, etc.) The enclosure 104 may contain a volatile corrosion inhibitor and/or a desiccant within the structure of the enclosure 104. Such films are known in the art, see, for example U.S. Pat. Nos. 4,290,912; 4,944,916; and 5,320,778. Once the enclosure 104 is hermetically sealed the anti-corrosion system contains a discrete atmosphere 108 where the concentration of either the volatile corrosion inhibitor and/or the desiccant is higher than the concentration of the volatile corrosion inhibitor and/or the desiccant outside the enclosure. Alternatively, the anti-corrosion system 100 can contain a desiccant service capsule 110 and/or an inhibitor service capsule 112 within the enclosure rather than such elements being self contained in the enclosure itself.
Such methods although effective are not suitable for all metals, non-metals, semi-precious and precious stones, and other valuable articles which may need to be protected. Additionally, such methods have service lives which are not suitable for some applications in which a long service life is necessary, for example, the protection of military equipment and/or hazardous materials.
The present invention relates to a method of protecting one or more articles from corrosion comprising the steps of: (A) placing the one or more articles to be protected in a corrosion protection system, the corrosion protection system comprising: a gas impermeable enclosure for holding one or more articles to be protected comprising at least one shell that is adapted to maintain an internal pressure greater than an external pressure outside of the corrosion protection system; (B) placing at least one corrosion preventing device into the gas impermeable enclosure, wherein the at least one corrosion preventing device is selected from a desiccant, a corrosion inhibitor, an inert gas, or a combination thereof; and (C) sealing the at least one shell of the gas impermeable enclosure.
In accordance with another aspect of the invention, a corrosion protection system comprises: a gas impermeable enclosure for holding one or more articles to be protected comprising at least one shell that is adapted to maintain an internal pressure greater than an external pressure outside of the corrosion protection system; and at least one corrosion preventing device located within the gas impermeable enclosure, wherein the at least one corrosion preventing device is selected from a desiccant, a corrosion inhibitor, an inert gas, or a combination thereof.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and features of the invention will become apparent from the following detailed description of the invention.